ABSTRACT:In the present investigation, an attempt was made to formulate the oral sustained release matrix tablets of Ambroxol HCl in order to improve efficacy, reduce the frequency of administration, and better patient compliance. Ambroxol Hydrochloride is a potent mucolytic agent capable of inducing bronchial secretions used in the treatment of respiratory disorders. Differential scanning calorimetric analysis confirmed the absence of any drug polymer interaction. Matrix tablets of Ambroxol Hydrochloride were formulated employing hydrophilic polymers HPMC K100M, Carbopol 934P and hydrophobic polymer Ethyl cellulose as release retardant polymers. The powder blend was evaluated for micromeritic properties. The sustained release matrix tablets were prepared by direct compression technique. The tablets were evaluated for thickness, diameter, weight variation test, hardness, friability, and drug content. The in vitro drug release characteristics were studied in simulated gastric fluid (2 hours) and intestinal fluid for a period of 6hours using USP type II dissolution apparatus (total 8hours). The results of dissolution studies indicated that formulation F3 (drug to polymer 1:1.06), the most successful of the study and exhibited satisfactory drug release in the initial hours and the total release was very close to the theoretical release profile. Matrix tablet containing HPMC K 100M (F3) formulation were found to show good initial release (14.8% in 2 hrs) and extended the release (90% in 11 hrs). The n value for F3 obtained from Korsmeyer – peppas model confirmed that the drug release was anomalous diffusion mechanism.